220 MORPHOLOGY AND EVOLUTION
vermiform appendix. Its base is expanded so that it appears to be a continuation of the csecum in the foetus, but it has the usual uniform calibre throughout in the adult. It is provided with a mesentery, and it is disposed in a coil or spiral according to Bischoff and Bolau. The large intestine, particularly the ascending colon, is short, Deniker has drawn attention to the rate of growth of the whole intestinal tract as well as of its components. He showed that the whole canal grows more rapidly than the body until the end of the milk dentition, but it diminishes afterwards. In the foetus it is 4'4 times the length of the body, but it is 4*2 times as long as the body in the adult. The small intestine grows more rapidly than the colon till the milk dentition is complete, whereas the reverse is the case after that period. The vermiform appendix increases during life, whereas it decreases as age advances in Man.
In the Orang-Outan the intestinal tract is very long, the ratio of the bodily length to that of the canal from the pylorus to the anus being 3 to 6" 13. Fick (247) gives the ratio as 1 to 4'3, which is similar to that in the Gorilla. In contradistinction to the Chimpanzee and Gorilla the valvulaB conniventes are very numerous; Bischoff denied their presence, but Barkow, Fick, Hartmann, Mayer, Owen and Sandifort describe or figure them. The vermiform appendix is very long, and arranged in a spiral as in the Gorilla. In the Gibbon the small intestine is 2'6 times the length of the body in the foetus (Deniker), but it is 3*7 to 5'9 times the length of the body after birth, according to the age of the animal. The duodenum is wide, and the common